As the game of basketball has increased in popularity, a greater number of people have purchased basketball systems for use at their homes. Such basketball systems typically include at least a pole to which a backboard and a goal are secured so that the goal is suspended above a playing surface. Although some basketball systems are permanently mounted into the ground near the home, or to the home itself, portable basketball systems are increasingly used. The advantages of portable basketball systems relative to permanently installed systems in general, and the relative merits of different portable basketball systems in particular, are detailed in application Ser. No. 08/100,054, and U.S. Pat. No. 5,248,140, which are incorporated herein by reference.
In either a portable or a permanently installed basketball system, it may be desirable to adjust the height of the goal above the playing surface. For instance, the basketball system may be used by relatively tall players for some games and by shorter players during other games. The basketball system may be used at different times by players of different strengths or skill levels. Or the basketball system may be used for regulation play at one time and for "dunking practice" at another time.
One approach to facilitating height adjustment of basketball goals involves clamping the backboard to the pole with one or more U-shaped bolts which are drawn against the pole by nuts threaded onto the ends of the bolts. By loosening the nuts, sliding the backboard along the pole, and re-tightening the nuts, one may alter the height of the goal.
However, bolting the backboard to the pole with U-bolts has several disadvantages when the time comes to adjust the goal's height. A wrench of the proper size is required to loosen and tighten the nuts. The bolt threads may be damaged or destroyed, and may be exposed to deterioration in outdoor systems from weathering. The bolts sliding along the pole tend to scratch the surface of the pole, marring its appearance and increasing its vulnerability to rust. Once the nuts are loosened, the backboard may slip suddenly downward under its own weight, injuring the user or damaging the basketball system. It may also be difficult to prevent the backboard from sliding down past the desired height. Thus, two or more people may be required: one to loosen and tighten the nuts, and a second to hold the backboard in the desired position.
Another approach to basketball goal height adjustment includes positioning a set bolt in a threaded hole in an outer length of pole, and positioning an inner length of pole telescopically within the outer length of pole. When the set bolt is tightened, the end of the set bolt presses against the outer surface of the inner length of pole.
The set bolt approach has many of the same disadvantages as the U-bolt approach just described. The threads on the set bolt may be damaged. The goal and backboard may slip suddenly when the set bolt is loosened. Or the set bolt may scratch the inner length of pole, particularly where the end of the set bolt is forced against the inner length of pole to hold the goal at a particular height.
A somewhat similar approach includes positioning one or more retaining pins through holes placed in both the inner and outer lengths of a telescoping pole. Because the pin goes through the inner pole length rather than resting against the outside surface of the inner pole, the risk of marring the inner pole is greatly reduced. However, the backboard may still slip suddenly when the retaining pin is removed. Moreover, once it is removed, the retaining pin is a loose piece which may easily be lost.
Another method for adjusting the height of a telescoping pole is disclosed in U.S. Pat. No. 5,098,092 issued to Aakre et al. A threaded extension shaft is connected via gears to a crankshaft having a handle. Rotation of the handle turns the gears, which turn the threaded extension shaft, thereby extending or retracting a portion of the basketball pole. A principal drawback of this approach is the weight of the extension shaft, gears, and related hardware. Lightweight portable basketball systems are preferable because they are more convenient and less expensive to ship, to position after assembly, and to store than heavier systems.
Yet another approach to facilitating height adjustment is to position a parallelogram-shaped structure between the backboard and the pole. Such an approach is disclosed in U.S. Pat. No. 4,805,904 issued to Nye. Use of the parallelogram structure is preferable to the U-bolt and set bolt approaches described above, because there are no threads to damage and little risk of marring the pole finish. There are no loose retaining pins to be lost. Moreover, the backboard is also constrained to prevent sudden large movements that may injure a user or damage the basketball system. However, the parallelogram structure contains several moving parts that may fail, and it includes several braces which add to the manufacturing cost, weight, and complexity of the basketball system.
Thus, it would be an advancement in the art to provide a height-adjustable basketball system wherein there is little risk that the backboard and goal will slip suddenly downward while the height of the goal above the playing surface is being adjusted.
It would be a further advancement in the art to provide such a basketball system wherein the height adjustment mechanism does not add substantially to the weight of the system.
It would also be an advancement in the art to provide such a basketball system which does not require the use of a wrench or other additional tool for height adjustment.
It would be a related advancement to provide such a basketball system which does not involve threads exposed to potential damage or rust.
Such a height-adjustable basketball system is disclosed and claimed herein.